Question

我想用手指从底部到顶部移动UIView，就像iOS的控制中心一样，尤其是与iOS的控制中心一样进行“平滑”移动（速度看起来有界，当速度很高时，没有需要用手指走远才能使UIView移到顶部等）。我的问题是：我可以使用任何预设或库来代替自己的自定义而不是精确的计算吗？我不太擅长于实现这种“平滑”效果，也许UIKit提供了一些在panGestureRecognizer处理程序中使用的功能，以平滑sender.translation之后的运动转换？

现在我的poseRecognizer处理程序是：

var y = sender.translation(in: view).y
let vy = sender.velocity(in: view).y

// we need to move constraintHeightInfoView.constant
// this is the height of my "ios control panel"

// i noticed the ios control panel move less if user tries 
// to move it out of screen bounds, so i'm first calculating 
// how much we are out of bound, in order to know "how much" 
// we will reduce velocity
var outofbound:CGFloat = 0
if(constraintHeightInfoView.constant < minH)
{
    outofbound = minH - constraintHeightInfoView.constant
}
else if(constraintHeightInfoView.constant > maxH)
{
    outofbound = constraintHeightInfoView.constant - maxH
}

// velocity target in pt/s
// i noticed the smooth effect in ios control panel includes 
// a velocity bound : if user pulls very fast the control panel, 
// it is not following the user finger, but it's a bit slower : 
// so there is a "vmax". When user release, i guess this vmax is 
// used for the final animation too 
let vtarget:CGFloat = 300 

print("\(y), \(vy), ofb : \(outofbound)")


// Here i'm lost : im trying to say : 
// if velocity above vtarget, reduce y so it match vtarget
if(abs(vy) > vtarget) {
    let dv = abs(vy) - vtarget
    y = // ????
}





switch sender.state {
    case .began, .changed :
    if case .began = sender.state {
        initialY = constraintHeightInfoView.constant
    }

    let newH = (expandInfoViewInitialY ?? minH) - y

    constraintHeightInfoView.constant = newH

    view.layoutIfNeeded()

case .ended :

    let heightTo:CGFloat
    let blurAlpha:CGFloat
    // 250 is the middle between top position and 
    // bottom position : if velocity is high, dont need to pull 
    // a lot to proceed the final release animation
    // if vy is 3000, even very small movement proceed the 
    // animation. Otherwise, if very slow movement, 
    // user needs to go at least at the middle between top and bottom (250)
    if(constraintHeightInfoView.constant > 250 - (-vy/300) * 50)
    {
        heightTo = maxH
        blurAlpha = 1
    }
    else
    {
        heightTo = minH
        blurAlpha = 0
    }


    // time of animation depends on remaining distance to bottom/top
    let dy = abs(self.constraintHeightInfoView.constant - heightTo)


    var t = dy / vtarget

    print("end : d:\(dy), t:\(t)")
    UIView.animate(withDuration:TimeInterval(t), delay:0,options:[.curveEaseOut], animations :{
        self.constraintHeightInfoView.constant = heightTo
        self.viewInfoBlurEffect.alpha = blurAlpha
        self.view.layoutIfNeeded()
    })

default :
    break
}

有了所有这些，我的过渡距离苹果控制中心的转变还很遥远……

Answer 1

如果将其设置为从上到下以及从上到下的动画效果，您将获得更加令人满意的体验。现在，将其“冻结”并通过UIViewPropertyAnimator从摇摄手势识别器中插入。这使其成为交互式动画。

例如，这将使您仅在用户拖动超过特定量的情况下“完成”动画即可。而且，您可以通过同一动画师同时执行轻按以关闭和拖动以关闭。

swift：完全像iOS控制面板一样平滑UIView的转换（跟随用户手指，使用平移）

1 个答案: